It's hard to prevent the hard to imagine

TACKLING terrorism demands an ability to get inside a
terrorist's mind, to conceive new methods of destruction. This is
the conclusion drawn in the official report into the September 11
attacks, which tried to explain what was a failure of imagination
 not "finding an expert who can imagine that aircraft could
be used as weapons".

A tremendous effort is now devoted to imagining the next
terrorist attack. Could it be poison in the water supply?
Radioactive medical waste bundled together with a bomb? Or, in one
of the stranger examples of this new art of conjecture about
potential threats, galactic terrorism? (Yes, an expert appeared on
television just after the Columbia space shuttle exploded in 2003
to speculate about a potential link with al-Qaeda.)

The proliferation of terrorism studies since September 11 has
drawn some well-deserved ridicule. Overblown is the title of
a recent book, arguing "how politicians and the terrorism industry
inflate national security threats".

But equally, the terrorists themselves have proven to be an
imaginative lot. Take the terrorist conspiracy foiled in the United
Kingdom in August last year: a plan to use liquid explosives hidden
in soft-drink bottles and destroy commercial jets crossing the
Atlantic. The scale of this plot, combined with the innovative bomb
design, threatened to kill thousands of people and cause massive
disruption to global commerce.

Despite the introduction of additional security barriers since
2001, and the billions of dollars spent worldwide in the campaign
against Islamist violence, terrorists remain patient and determined
to carry out further attacks.

"What makes al-Qaeda such a dangerous creature is its ability to
marry ideological intensity with organisational resilience and
adaptability," the chief of the Australian Security Intelligence
Organisation told a conference last month. This describes the key
element of

the worldwide terrorist threat extending to Australia 
persistence.

The failed attacks in the UK last weekend show how a creative
plot can test the counter-measures put in place by authorities.
Strict controls now limit the purchase of certain types of
chemicals and fertilisers, the so-called precursor ingredients that
can be assembled into a bomb. Any bulk purchases are screened and
often require a permit.

So the perpetrators in the UK looked elsewhere and compiled a
crude yet potentially deadly bomb from materials available in
everyday life  a mix of gas cylinders, petrol and nails.
Finding a way to govern access to such otherwise mundane items will
be expensive, and perhaps ultimately, impossible.

And besides, terrorists will keep searching for new ways to
surprise authorities and shock the public.

What makes combating modern terrorism even more difficult is
that operatives are not limited by the usual concern for
self-preservation. After the first two bombs failed to detonate in
London  the remote trigger was apparently a mobile phone
 it appears the attempt to bomb the Glasgow airport was
intended as a suicide mission. The driver and his passenger rammed
their car into the terminal, hoping to sacrifice their own lives to
ensure the sinister payload actually exploded and caused maximum
devastation.

The terrorist threat in the UK is made worse by a confluence of
factors. First is the appeal of violent Islamist ideology to a
disaffected minority in the Muslim community. This does not amount
to many people, but it is enough to give succour to those willing
to carry out attacks. Second is the strong personal connections
British Muslims have with South Asia, particularly Pakistan. This
provides al-Qaeda a potential conduit to tap into Muslim
malcontent, to teach terrorist methods such as bomb-making and to
direct attacks.

While the threat in the UK is the most immediate of all Western
countries, the terrorist problem is still wider. In Australia,
Prime Minister John Howard warned: "What is happening in Great
Britain is a reminder to all of us that, despite all the talk on
occasions from some that the threat of terrorism is exaggerated in
our society, it is not, and we must remain vigilant."

Howard is restating an important truism: governments can limit
the risk of a terrorist attack, never eliminate the threat
altogether.

Australia's problem is of a different character and scale than
the threat confronting the UK. But common elements are evident in
both countries. Most obvious is the means extremists use to extend
their network of sympathisers. The internet helps connect family
and business across the world, but it has also become a powerful
tool for the grooming and recruitment of extremists.

Video clips of attacks on US forces in Iraq mingle online with
the diatribes of Islamist ideologues calling for further attacks on
the West. Al-Qaeda's deputy, Ayman al-Zawahiri, has released at
least five lengthy statements this year alone in his own running
commentary on international affairs. The video versions often carry
English subtitles in a deliberate strategy to expand his audience.
And the internet also serves as an anonymous forum for extremists
to learn skills, such as bomb-making.

The potential for a self-radicalised and self-intiated terrorist
makes the next attack that much harder to imagine.